Long-term Debt	6 Months Ended
Oct. 31, 2015
Long-term Debt [Abstract]
Long-term Debt	Note D - Long-term Debt The Company has a senior secured credit facility with Wells Fargo, N.A. with a credit limit up to $30,000,000 and current term through October 31, 2017. The credit facility is collateralized by substantially all of the domestically located assets of the Company and the Company has pledged 65% of its equity ownership interest in some of its foreign entities. The Company is required to be in compliance with several financial covenants. The facility allows the Company to choose among interest rates at which it may borrow funds: the bank fixed rate of two and one quarter percent plus one percent (effectively 3.25% at October 31, 2015) or LIBOR plus two and one quarter percent (effectively 2.625% at October 31, 2015). Interest is paid monthly. Under the senior secured credit facility, the Company may borrow up to the lesser of (i) $30,000,000 or (ii) an amount equal to the sum of 85% of the receivable borrowing base plus a percentage of the inventory borrowing base (collectively, “Borrowing Base”), which cannot exceed 50% of combined eligible receivables and inventory. Further, in specific circumstances, the Company was entitled to an over-advance of up to $5,000,000 through October 31, 2015; however, at no time could the borrowings under the credit facility exceed $30,000,000. The effective interest rate for the over-advance facility was LIBOR plus two and three quarter percent. Further, the senior secured credit facility agreement was modified to allow specific foreign receivables to become eligible collateral. The receivable modification was effective until June 30, 2015. As of October 31, 2015, there was a $21,000,000 outstanding balance and $6,856,069 of unused availability under the credit facility agreement. At October 31, 2015, the Company was in compliance with its financial covenants. The Company entered into a mortgage agreement on January 8, 2010, in the amount of $2,500,000, with Wells Fargo, N.A. to refinance the property that serves as the Company’s corporate headquarters and its Illinois manufacturing facility. The Wells Fargo, N.A. note historically bore interest at a fixed rate of 6.42% per year and was amortized over a sixty month period. A final payment of approximately $2,000,000 was due on or before January 8, 2015. On November 24, 2014, the Company refinanced the mortgage agreement with Wells Fargo, N.A. The note requires the Company to pay monthly principal payments in the amount of $9,500, bears an interest rate of LIBOR plus two and one-quarter percent (effectively 2.625% at October 31, 2015) and is payable over a sixty month period. A final payment of approximately $2,289,500 is due on or before November 8, 2019. The outstanding balance as of October 31, 2015 was $2,745,500. Note D - Long-term Debt - Continued The Company entered into a mortgage agreement on October 24, 2013, in the amount of $1,275,000, with Wells Fargo, N.A. to finance the property that serves as the Company’s engineering and design center in Elgin, Illinois. The Wells Fargo, N.A. note requires the Company to pay monthly principal payments in the amount of $4,250, bears interest at a fixed rate of 4.5% per year and is payable over a sixty month period. A final payment of approximately $1,030,000 is due on or before October 2018. The outstanding balance as of October 31, 2015 was $1,173,000.

Note D - Long-term Debt

The Company has a senior secured credit facility with Wells Fargo, N.A. with a credit limit up to $30,000,000 and current term through October 31, 2017. The credit facility is collateralized by substantially all of the domestically located assets of the Company and the Company has pledged 65% of its equity ownership interest in some of its foreign entities. The Company is required to be in compliance with several financial covenants. The facility allows the Company to choose among interest rates at which it may borrow funds: the bank fixed rate of two and one quarter percent plus one percent (effectively 3.25% at October 31, 2015) or LIBOR plus two and one quarter percent (effectively 2.625% at October 31, 2015). Interest is paid monthly. Under the senior secured credit facility, the Company may borrow up to the lesser of (i) $30,000,000 or (ii) an amount equal to the sum of 85% of the receivable borrowing base plus a percentage of the inventory borrowing base (collectively, “Borrowing Base”), which cannot exceed 50% of combined eligible receivables and inventory. Further, in specific circumstances, the Company was entitled to an over-advance of up to $5,000,000 through October 31, 2015; however, at no time could the borrowings under the credit facility exceed $30,000,000. The effective interest rate for the over-advance facility was LIBOR plus two and three quarter percent. Further, the senior secured credit facility agreement was modified to allow specific foreign receivables to become eligible collateral. The receivable modification was effective until June 30, 2015. As of October 31, 2015, there was a $21,000,000 outstanding balance and $6,856,069 of unused availability under the credit facility agreement. At October 31, 2015, the Company was in compliance with its financial covenants.

The Company entered into a mortgage agreement on January 8, 2010, in the amount of $2,500,000, with Wells Fargo, N.A. to refinance the property that serves as the Company’s corporate headquarters and its Illinois manufacturing facility. The Wells Fargo, N.A. note historically bore interest at a fixed rate of 6.42% per year and was amortized over a sixty month period. A final payment of approximately $2,000,000 was due on or before January 8, 2015. On November 24, 2014, the Company refinanced the mortgage agreement with Wells Fargo, N.A. The note requires the Company to pay monthly principal payments in the amount of $9,500, bears an interest rate of LIBOR plus two and one-quarter percent (effectively 2.625% at October 31, 2015) and is payable over a sixty month period. A final payment of approximately $2,289,500 is due on or before November 8, 2019. The outstanding balance as of October 31, 2015 was $2,745,500.

Note D - Long-term Debt - Continued

The Company entered into a mortgage agreement on October 24, 2013, in the amount of $1,275,000, with Wells Fargo, N.A. to finance the property that serves as the Company’s engineering and design center in Elgin, Illinois. The Wells Fargo, N.A. note requires the Company to pay monthly principal payments in the amount of $4,250, bears interest at a fixed rate of 4.5% per year and is payable over a sixty month period. A final payment of approximately $1,030,000 is due on or before October 2018. The outstanding balance as of October 31, 2015 was $1,173,000.